ACTIVITY OF BRINCIDOFOVIR (BCV) AGAINST MURINE POLYOMAVIRUS (MUPYV) IN A MOUSE INFECTION MODEL

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1 ACTIVITY OF BRINCIDOFOVIR (BCV) AGAINST MURINE POLYOMAVIRUS (MUPYV) IN A MOUSE INFECTION MODEL Kidney Week 2018 Poster # SA-PO642 BRINCIDOFOVIR(BCV) DEMONSTRATES ANTIVIRAL ACTIVITY AGAINST MURINE POLYOMAVIRUS (MUPYV) IN A MOUSE MODEL OF ACUTE INFECTION Kidney Week 2018 Poster # SA-PO641

2 BCV Background BCV is a lipid conjugate of the nucleotide analog cidofovir (CDV, CMX021). The lipid conjugate facilitates entry of BCV into the cell via endogenous lipid uptake pathways. 1,2 Intracellularly, BCV is converted to active cidofovir diphosphate (CDV-PP). CDV-PP exerts an antiviral effect by acting as a potent alternate substrate inhibitor of viral DNA synthesis. 3 Gastrointestinal events (e.g., diarrhea) have been dose limiting with longer-term oral BCV dosing. 4, 5 The development of an IV formulation of BCV has demonstrated improved tolerability allowing administration of higher doses or longer durations of BCV. 6 IV BCV facilitates delivery of consistent concentrations of BCV and CDV-pp to tissues, including the kidney, allowing for improved efficacy against viruses with kidney tropism such as BK virus. 1. Painter GR & Hostetler KY. Trends Biotechnol. 2004;22: Lanier R, et al. Viruses. 2010;2: Xiong X, et al. Antimicrob Agents Chemother. 1997;41: Prasad VK, et al. Biol Blood Marrow Transplant. 2017;23:S57-S8 [abstract]. 5. Grossi IM, et al. The Toxicologist: Supplement to Toxicological Sciences, Society of Toxicology. 2017:[abstract 1687] 6. Poster # 1421 presented at ID Week Congress, San Francisco, CA, USA, October 3-7,

3 Genetic Organization of Polyomavirus 3 Polyomaviruses are a family of small DNA viruses that persistently infect their hosts for life. Human polyomavirus, BKV, is responsible for kidney transplant rejections. Since polyomaviruses are species-specific, the MuPyV-mouse model enables study of polyomavirus pathogenesis in a natural host. Closed circular dsdna molecule Transcription is bidirectional from ORI in the NCCR Early coding region encodes large T (TAg) and small T (tag) Late coding region encodes structural proteins VP1, VP2 and VP3 Large T antigen is a multi-function protein TAg stimulates cell cycle progression and counteracts apoptosis ATPase/helicase Binds to host DNA polymerase; role in DNA replication

4 Mean Change from Baseline in egfr (ml/min/1.73m 2 ) Improved Renal Function in HCT Recipients on BCV: Evidence of Potential Effect on BKV 20 Mean (N) Change from Baseline in egfr (ml/min/1.73 m 2 ) by Visit and Dose in Study Wk 2 Wk 4 Wk 6 Wk 8 Wk 10 Wk 12 Time of Dosing (from randomization into Study 201) BCV 200 mg QW BCV 100 mg BIW BCV 100 mg QW BCV 40 mg QW Placebo p<0.05 egfr: estimated glomerular filtration rate Data from Study 201 presented at BMT Tandem, February Baseline GFR Week 2 Week 4 Week 6 Week 8 Week 10 Post-Week 1 Placebo -7 (56) -9 (46) -10 (35) -19 (36) -15 (21) -13 (57) Brincidofovir 100 mg BIW -5 (49) -3 (44) 1 (33) 12 (31) 6 (21) 8 (49) p= p= p=0.0025

5 PROPHYLAXIS ANIMAL MODEL SA-PO642 5

6 BCV Prophylaxis in an Acute MuPyV Infection Model BCV Dose (mg/kg BiW) Viral Inoculum Female B6 Mice (n=) Day 1 interim tissue collection a b b a Day 1 (n=3/dose group) tissue collection (pre-3 rd BCV dose) b Day 5 (n=3 / BCV dose group) to provide comparison of BCV/CDVpp exposures in infected vs non-infected mice 6 Endpoints Viral load in kidney at day 5 by qpcr Kidney BCV and CDV-pp concentrations Plasma BCV concentrations (in progress)

7 Viral Genome qpcr- Kidney (10 6 initial viral inoculum) 20 mg/kg i.p BCV decreased viral load in the kidney by ~1 log ** 10 4 and 10 5 inoculum undetectable in kidney at Day 5 7 n=5; Bars represent mean ± SD; Mann-Whitney test- ** p<0.01

8 CDV-pp (ng/g) Kidney CDV-pp in infected and uninfected animals Kidney CDV-pp CMX001-VIR-105 (prophylaxis) Day 5- (24 hours post last of 4 BIW doses) uninfected infected uninfected infected 20 mg/kg BIW 40 mg/kg BIW CDV-pp concentrations in kidney on Day 1 were below limit of detection (data not shown). Day 1 collection (prior to infection) was 3 days after most recent BCV dose. Kidneys collected on Day 5 (24 hours after most-recent BCV dose) demonstrated dose responsive levels of tissue CDV-pp. Inter-animal variability led to inconclusive findings regarding infected vs. uninfected CDV-pp concentrations. 8

9 Conclusions BCV reduced MuPyV viral load when administered 20 mg/kg via IP administration to mice given 2 BIW doses of BCV pre- and post-infection. While this experiment evaluated the prophylactic administration of BCV, undetectable levels of CDV-pp in the kidney on the day of infection (Day 1) suggests that BCV could be effective in a treatment scenario. Additional data are being generated to characterize the pharmacokinetics (PK) of BCV and CDV-pp in the plasma and kidney of mice given BCV via IP administration to facilitate comparison to human plasma exposure 9

10 TREATMENT ANIMAL MODEL SA-PO641 10

11 Terminal CMX001-VIR-110: Post Infection BCV I.P. Via 3 Dosing Regimens Infection (10 6 ) i.p. BCV (mg/kg) 11 Group 1 Group 2 Group 3 Group 4 Group 5 Uninfected Placebo Infected Single Dose Placebo Infected Daily Placebo Infected BIW Placebo Infected Single Dose Endpoints Kidney viral load at Day 7 by qpcr Kidney CDV-pp concentrations at Day 7 Plasma BCV concentrations at Day 7 n= Day 0 Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day Group 6 Infected Daily Group 7 Infected BIW

12 BCV demonstrates antiviral activity in the kidneys of mice infected with MuPyV 12 Bars represent mean ± SD; Mann-Whitney test- *** p<0.001

13 CDV-pp (ng/g) Mouse Kidney CDV-pp seen at all doses Kidney BCV CMX001-VIR-110 (treatment) Collected Day 7 (after 1 week txt regimen) Kidney CDV-pp CMX001-VIR-110 (treatment) Collected Day 7 (after 1 week txt regimen) mg/kg 13 mg/kg QD 40 mg/kg BIW 80 mg kg QW mg/kg 13 mg/kg QD 40 mg/kg BIW 80 mg kg QW 13

14 Treatment Model Conclusions BCV reduced MuPyV viral load in the kidney 2 log 10 when administered to MuPyV infected mice once weekly at 80 mg/kg, twice weekly at 40 mg/kg, or daily for 6 days at 13 mg/kg via IP administration. Six days after a single 80 mg/kg dose, viral load was reduced in the presence of no detectable kidney BCV and ~ 30 ng/g CDV-pp. These data suggest the potential to employ a once weekly dosing regimen. Additional data are being generated to characterize the pharmacokinetics (PK) of BCV and CDV-pp in the plasma and kidney of mice given BCV via IP administration to facilitate comparison to human plasma exposure. 14